共查询到20条相似文献,搜索用时 15 毫秒
1.
E. I. Zhilyaeva V. N. Semkin E. I. Yudanova R. M. Vlasova S. A. Torunova A. M. Flakina G. A. Mousdis K. V. Van A. Graja A. Lapinski R. B. Lyubovskii R. N. Lyubovskaya 《Russian Chemical Bulletin》2010,59(7):1360-1368
New conducting radical cation salts (EDT-TTF)3Hg 2Br6, (TMET) 5Hg(SCN) 4-xIx (x≈0.35), and (EDT-TTF)3Hg(SCN)3I0.5(PhCl)0.5 were synthesized. Their conductivities, ESR and polarized reflectance spectra were studied. It was shown that the organic conductors with differently oriented conducting layers (EDT-TTF)3Hg2Br6 and (TMET)5Hg(SCN)4-xIx (x≈?0.35) are characterized by the quasi-one-dimensional character of electron motion. The conductivity along and across conducting layers has a semiconductive character. It was established by ESR and polarized reflectance spectroscopy that the properties of such conductors are a superposition of the properties of individual conducting layers. 相似文献
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Cao P Li H Zhang P Calzaferri GA 《Langmuir : the ACS journal of surfaces and colloids》2011,27(20):12614-12620
We report important progress made in the synthesis of oriented functional layers of nanochannel materials by using coordination chemistry as a tool. Zeolite L (ZL) crystals have been arranged into oriented layers through the coordinative interactions between a functional organic linker (L) and metal cations used for connecting the different parts. As organic linker we used a terpyridyl ligand bearing a urea group and a reactive siloxane part. Two strategies that lead to monolayers with different properties are described. The first consists of reacting the siloxane group of ligand L with OH groups of the substrate (S), and selectively reacting the siloxane group of L with OH groups located at the base of the ZL crystals. Next, metal cations M(n+), for example, Zn(2+) or Cu(2+), are coordinated to the terpy group on the modified substrate. To this the modified ZL is added and coordinatively bound by the terpy(Mn(n+))terpy interaction, leading to oriented ZL layers. The second method consists of reacting substrate S and ligand L in the presence of a metal cation. A layer with reactive siloxane groups is formed on S to which the ZL crystals are bound by the reaction of the hydroxyl groups of their base. Zn(2+), Cu(2+), and lanthanide ions Eu(3+) and Tb(3+)have been tested successfully, all of them leading to high-quality ZL monolayers with open channels, accessible for accepting guests, oriented perpendicularly with respect to the surface of S. 相似文献
4.
J. W. G. Bentz H. -P. Ewinger J. Goschnick G. Kannen H. J. Ache 《Fresenius' Journal of Analytical Chemistry》1993,346(1-3):123-127
Summary Previous work on the quantification and localization of organically bound elements with plasma-based SNMS for the characterization of microparticles has been continued. Relative detection factors for 10 elements have been determined. Except for lead and bromine a principle proportionality to atomic ionization probabilities is shown. A moderate matrix dependence of less than 40% variation was found even when inorganic and organic materials are included. For depth calibration, erosion rates of organic materials were determined from the time interval necessary to sputter through planar single-layers and Langmuir-Blodgett multi-layer systems with known thickness, as well as from gravimetric powder measurements. Depth propagation rates were 0.7 nm·sec–1 for polymers and 2.3 nm·sec–1 for aromatic compounds, when 400 eV argon ion bombardment with 0.7 mA·cm–2 was used. A depth resolution of 30 nm has been obtained. Model particles of 5 m size have been coated with fluoranthene. Inspection with SNMS revealed an incomplete coating covering only 20% of the microparticle surface with an average thickness of the partial coating of 300 nm. Subsequent characterization using laser-induced fluorimetry confirmed the amount of fluoranthene coating measured by SNMS. 相似文献
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Functional thin layers based on polypyrrole were used in electrochemical sensors as mixed conducting interfaces between ion‐selective membranes and the wiring. In particular, new types of ion‐selective electrodes for potentiometric measurement of pH value and concentration of sulfate ions in solutions were developed. The resulting electrodes do not need any inner liquid junction. First determinations of the sensor parameters sensitivity, selectivity and long term stability indicate a good performance of the prepared sensors. The results imply that interfaces, containing polypyrrole, could be an interesting basis for the construction of a new type of all‐solid‐state ion‐selective electrodes. 相似文献
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Liang L Liu J Windisch Jr CF Exarhos GJ Lin Y 《Angewandte Chemie (International ed. in English)》2002,41(19):3665-8, 3520
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Julian M. Rotter Roman Guntermann Michael Auth Andre Mhringer Andreas Sperlich Vladimir Dyakonov Dana D. Medina Thomas Bein 《Chemical science》2020,11(47):12843
Covalent organic frameworks (COFs) define a versatile structural paradigm combining attractive properties such as crystallinity, porosity, and chemical and structural modularity which are valuable for various applications. For the incorporation of COFs into optoelectronic devices, efficient charge carrier transport and intrinsic conductivity are often essential. Here, we report the synthesis of two imine-linked two-dimensional COFs, WTA and WBDT, featuring a redox-active Wurster-type motif based on the twisted tetragonal N,N,N′,N′-tetraphenyl-1,4-phenylenediamine node. By condensing this unit with either terephthalaldehyde (TA) or benzodithiophene dialdehyde (BDT), COFs featuring a dual-pore kagome-type structure were obtained as highly crystalline materials with large specific surface areas and mesoporosity. In addition, the experimentally determined high conduction band energies of both COFs render them suitable candidates for oxidative doping. The incorporation of a benzodithiophene linear building block into the COF allows for high intrinsic macroscopic conductivity. Both anisotropic and average isotropic electrical conductivities were determined with van der Pauw measurements using oriented films and pressed pellets, respectively. Furthermore, the impact of different dopants such as F4TCNQ, antimony pentachloride and iodine on the conductivities of the resulting doped COFs was studied. By using the strong organic acceptor F4TCNQ, a massive increase of the radical cation density (up to 0.5 radicals per unit cell) and long-term stable electrical conductivity as high as 3.67 S m−1 were achieved for the anisotropic transport in an oriented film, one of the highest for any doped COF to date. Interestingly, no significant differences between isotropic and anisotropic charge transport were found in films and pressed pellets. This work expands the list of possible building nodes for electrically conducting COFs from planar systems to twisted geometries. The achievement of high and stable electrical conductivity paves the way for possible applications of new COFs in organic (opto)electronics.Covalent organic frameworks define a versatile structural paradigm combining various attractive properties. The impact of different dopants on the conductivity of imine-linked 2D COFs featuring a redox-active Wurster-type motif was studied. 相似文献
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T. Uchida M. Wakakura A. Miyake T. Ogawa 《Journal of Thermal Analysis and Calorimetry》2008,93(1):47-52
In this study, we evaluated the reactivity of organic peroxides with metals. The effect of the metals on the decomposition
of organic peroxides was measured using a differential scanning calorimeter (DSC). Results of DSC measurements showed that
some organic peroxides have high reactivity with a gold plated cell. Especially, hydroperoxides were decomposed at lower temperature
using the gold plated cell when compared to other type of cells.
In order to evaluate the effect of metals on the hydroperoxides, the decomposition characteristics of cumenhydroperoxide (CHP)
with metal powders were studied using a C80 calorimeter and the products were analyzed by a gas chromatograph. These results
indicated that the radical reaction of CHP was catalyzed by the gold and the autocatalytic reaction of CHP was catalyzed by
stainless steel (SUS) and hastelloy c (HC). 相似文献
10.
Klaus-Dieter Schierbaum Andreas Gerlach Wolfgang Göpel Walter M. Müller Fritz Vögtle Andreas Dominik Hermann J. Roth 《Fresenius' Journal of Analytical Chemistry》1994,349(5):372-379
Modified calixarenes can be used as model compounds to study molecular recognition since their molecular cavities reversibly incorporate small organic molecules. This effect has been used in chemical sensors with bulk and surface acoustic wave devices, coated with thin calixarene layers. These devices sensitively convert the mass changes during molecule/calixarene interactions into electronic signals. Thin films of modified calixarenes were prepared with various side groups and various sizes by Knudsen sublimation under well-defined, ultra-high-vacuum conditions. The interaction with perchloroethylene, chloroform, benzene, and toluene at constant temperatures, T, and partial pressures, pi, was studied systematically for different film thicknesses, d, by means of mass changes m=f(T,p
i,d). From the thickness dependence of values, meq, obtained under thermodynamic equilibrium conditions, surface and bulk effects during molecule calixarene interactions were separated. Pronounced excesses of surface concentrations of organic molecules have been found. Activation energies for molecular desorption from surface sites and for diffusion to subsurface sites were determined from mass spectroscopic results of thermal desorption behaviour. Experimental data of adsorption and desorption energies were confirmed by theoretical force field calculations. 相似文献
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Green chemistry oriented organic synthesis in water 总被引:2,自引:0,他引:2
The use of water as solvent features many benefits such as improving reactivities and selectivities, simplifying the workup procedures, enabling the recycling of the catalyst and allowing mild reaction conditions and protecting-group free synthesis in addition to being benign itself. In addition, exploring organic chemistry in water can lead to uncommon reactivities and selectivities complementing the organic chemists' synthetic toolbox in organic solvents. Studying chemistry in water also allows insight to be gained into Nature's way of chemical synthesis. However, using water as solvent is not always green. This tutorial review briefly discusses organic synthesis in water with a Green Chemistry perspective. 相似文献
12.
K. Bhaskara Rao 《Fresenius' Journal of Analytical Chemistry》1961,180(4):271-275
Summary A rapid volumetric method for the estimation of nickel has been proposed. The procedure consists of the precipitation of nickel with dimethylglyoxime followed by the hydrolysis of the oxime in hydrochloric acid solution and the titration of hydroxylamine formed with permanganate using cupric chloride as catalyst.Published by permission of the Director, Mines Branch, Department of Mines and Technical Surveys, Ottawa, CanadaAt present National Research Council of Canada Post-doctorate Research Fellow 相似文献
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Iris Maege Evelin Jaehne Axel Henke Hans-Juergen P. Adler Christian Bram Christian Jung Martin Stratmann 《Macromolecular Symposia》1998,126(1):7-24
The adsorption and self-organisation process of alkyl-phosphonic acids and phosphoric acid monoalkyl esters on technical aluminium surfaces have been investigated by different surface sensible techniques: Grazing angle FT-IR- spectroscopy, angle dependent XPS and Auger- spectroscopy. The aim of these studies was to replace the present technical procedure for pretreatment of aluminum surfaces with Chromate acid in order to improve the corrosion inhibition and the coating adhesion. The ability for self-assembly is given by substances which have a surface reactive group and a long-aliphatic or aromatic spacer and a supramolecular order is built-up between these spacers. The results show that these molecules are able to adsorb spontaneously onto the aluminum surface and subsequently a structured molecular order is formed. These effects were confirmed by industrial linked adhesion and corrosion tests. 相似文献
14.
Artificial synapses based on organic electrochemical transistors with self-healing dielectric layers
Yushan Gao Junyao Zhang Dapeng Liu Tongrui Sun Jun Wang Li Li Shilei Dai Jianhua Zhang Zhenglong Yang Jia Huang 《中国化学快报》2024,(3):452-456
Organic electrochemical transistors(OECTs) have emerged as one type of promising building block for neuromorphic systems owing to their capability of mimicking the morphology and functions of biological neurons and synapses. Currently, numerous kinds of OECTs have been developed, while self-healing performance has been neglected in most reported OECTs. In this work, the OECTs using self-healing polymer electrolytes as dielectric layers are proposed. Several important synaptic behaviors are simul... 相似文献
15.
Elastic deformations induced by an electric field in homeotropic nematic layers with finite anchoring energy were studied numerically. A nematic material possessing flexoelectric properties and characterized by a positive dielectric anisotropy was considered. The ionic space charge and the ion transport across the layer were taken into account. The director orientation, the electric field strength and the ion concentrations were calculated as functions of the coordinate normal to the layer. The calculations show that the electric field distribution, which determines the form of the deformations, is influenced by the ionic current and therefore depends on the ionic content and on the properties of the electrodes. Several types of deformations were distinguished. When the electrode contacts are well conducting or when the ionic content is low, the threshold voltage is very close to the value U f valid for an insulating nematic. When the electrodes are poorly conducting or blocking at high ion concentration, the threshold voltage decreases much below U f. At moderate ion concentrations, i.e. between 1019 and 1020 m?3, two different behaviours were found depending on the sign of the sum of flexoelectric coefficients e 11+e 33. In the case of e 11+e 33<0, the threshold voltage decreases with the ionic content; in the case of e 11+e 33>0, the deformations occur in two separate voltage regimes. They arise above a certain threshold voltage, disappear at some higher voltage and reappear at an even higher threshold. 相似文献
16.
Tibor Ižák Marián Marton Marián Vojs Robert Redhammer Marián Varga Marián Veselý 《Chemical Papers》2010,64(1):46-50
This study is focused on Raman spectroscopy investigations of differently deposited diamond-like carbon (DLC) layers due to varying: (i) Ar and/or N2 flow rate, (ii) number of impulses, and (iii) bias voltage during the growth process. Samples were prepared by a physical vapor deposition method in a pulse arc system. It is shown that Ar and N2 flow rates as well as the bias voltage influence the morphology and chemical composition of the deposited DLC layers. By changing the number of impulses, the number of carbon atoms sputtered from target in the vacuum chamber changes, which is reflected in the thickness and morphology of the DLC layers. Visible light Raman spectroscopy of 632 nm excitation wavelength was used for deep analysis of the deposited layers. 相似文献
17.
Layer-by-layer growth of oriented metal organic polymers on a functionalized organic surface 总被引:1,自引:0,他引:1
Shekhah O Wang H Strunskus T Cyganik P Zacher D Fischer R Wöll C 《Langmuir : the ACS journal of surfaces and colloids》2007,23(14):7440-7442
A metal-organic coordination polymer based on benzenetricarboxylic acid ligands and Zn(II) ions was grown on a COOH-terminated organic surface in a stepwise fashion. The deposited films were characterized using a number of surface analysis techniques, including X-ray absorption spectroscopy and X-ray photoelectron spectroscopy. IR measurements show that the metal-organic coordination polymer grows in a layer-by-layer fashion and can be reversibly loaded with NH3. The deposition is very selective and occurs only on COOH-terminated regions of an organic surface, as demonstrated by AFM measurements. 相似文献
18.
V. S. Rudnev D. L. Boguta P. M. Nedozorov T. A. Kaidalova 《Russian Journal of Applied Chemistry》2006,79(2):256-263
Results obtained in studying the elemental and phase composition of anodic layers formed on titanium, aluminum, niobium, and zirconium under the action of electric discharges in aqueous electrolytes with hexametaphosphate complexes of Ni(II), Mg(II), and Mn(II) are presented. 相似文献
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Carmeli I Lewin A Flekser E Diamant I Zhang Q Shen J Gozin M Richter S Dagan Y 《Angewandte Chemie (International ed. in English)》2012,51(29):7162-7165
Control over the T(c) value of high-T(c) superconductors by self-assembled monolayers is demonstrated (T(c) = critical temperature). Molecular control was achieved by adsorption of polar molecules on the superconductor surface (see scheme) that change its carrier concentration through charge transport or light-induced polarization. 相似文献